1. Field of the Invention
The present invention relates to generally a system for controlling display of digit position marks such as a comma display control system and more particularly a system adapted to automatically suppress the display of a digit position mark such as a comma in the digit place where the most significant digit of the number is displayed.
2. Description of the Prior Art
The system for suppressing the zero display incorporated in an electronic desktop calculator has been well known to the art and is, for instance, disclosed in U.S. Pat. No. 3,432,845. However, a comma which is used to separate a number displayed into thousands, millions, and other groups of a predetermined number of digits, usually, three digits, is generally not suppressed. There has been devised and demonstrated a system for suppressing a comma or commas in the digit places, where zero suppression is made, by utilizing the zero suppression signal. However, it is extremely difficult or impossible for this system to suppress a comma in the digit place where the most significant digit of the number is displayed. Furthermore the above system is very complex in construction, large in size and very expensive to manufacture.
Furthermore, in the prior art time division display systems, it is difficult to energize the displaying elements for a longer period of time than the time in which one digit is displayed every cycle under the influence of the duty cycle, operating speed of the machine and the brightness of the display used in the machine.
In view of the above, one of the objects of the present invention is to provide a system for controlling display of digit position marks which may suppress the mark such as comma in the digit place where the most significant digit of the number is displayed.
Another object of the present invention is to provide a novel system which may suppress not only a mark such as a comma in the digit place where the most significant digit of the number is displayed but also zeros in the digit places higher than the digit place of the most significant digit.
Still another object of the present invention is to provide a system for controlling a numeral display in which the brightness of the display is improved and the flicker is eliminated by holding the displayed information during a time period corresponding to more than one digit time.
Still another object of the present invention is to provide an improved system for controlling the numeral display in which overlapped displaying of the numeral, beat and noise are prevented by inserting blanking between adjacent display information signals applied to the displaying units.
The above and other objects, features and advantages of the present invention will become more apparent from the following description of some preferred embodiments thereof taken in conjunction with the accompanying drawing.